Vol 62, No 7 (2017)

A novel cadmium compound, [(CdI₃)₂(μ₂-I)]₂(Me₂-4,4'-H₂bipy)₃ (1) (Me = methyl; 4,4'-bipy = 4,4'-bipyridine) with the Me₂-4,4'-H₂bipy moiety generated in situ, has been prepared through a solvothermal reaction and structurally characterized by X-ray single crystal diffraction analysis. Compound 1 is characterized by an isolated structural motif, consisting of [(CdI₃)₂(μ₂-I)]^3– anions and Me₂-4,4'-H₂bipy²⁺ cations. The [(CdI₃)₂(μ₂-I)]^3– anions and Me₂-4,4'-H₂bipy²⁺ cations interconnect together via C–H···I hydrogen-bonding interactions to complete a three-dimensional (3D) supramolecular network. Solid state fluorescent spectrum reveals an emission band in the violet region.

Despite of the permanent progress of technique and finding of the new, modern materials that successfully replace metals, steel continues to play an important role in the technical practice. The tendency is to discover the new alloys with better mechanical and technological characteristics, compared to conventional and standard types of steels. High-alloyed Cr–Mo steel, with a high content of Vanadium is the new type of wear resistant material, with high hardness and satisfactory impact and fracture toughness. During the solidification process Vanadium, as a strong carbide forming element, creates a network of M₇C₃ type carbide grains around the metal matrix, while in the matrix, the finely dispersed V₆C₅ type carbides are formed. In this paper, the chemical composition and morphology have been studied of carbides and the other phases present in the metal matrix in 1.4 wt % C, 12 wt % Cr, 1.0 wt % Mo steels with additions up to 3.0 wt % V. Experimental results indicate that Vanadium affects the solidification process in high Chromium steel. Vanadium is distributed between eutectic M₇C₃ carbide and the matrix, but its content in carbides is considerably higher. Vanadium changed the microstructure parameters of phases present in the structure of alloys, including volume fraction, size and morphology.

The crystal structure of 4-aminopyridinium 3,5-dinitrobenzoate, C₁₂H₁₀O₆N₄, has been determined by single-crystal X-ray diffraction technique. The title compound crystallizes in the monoclinic sp. gr. P21/n with the unit cell parameters: a = 7.4726(3) Å, b = 23.0898(9) Å, c = 8.0744(4) Å, V = 1338.64(10) ų, Z = 4. The asymmetric unit of the compound consists of one 3,5-dinitrobenzoate anion and 4-aminopyridine cation. The adjacent anions and cations are linked through two N−H···O hydrogen bonds, N2−H2A···O5 and N₂−H2B···O6, to form an infinite chain of anions and cations, extended along the [010] direction.

The reaction of AgNO₃ with combinations of 1,3-bis(4-pyridyl)propane (bpp) and 1,3,5-benzenetricarboxylic acid (H₃btc) in aqueous alcohol/ammonia at room temperature produces crystals of {[Ag₆(H₂O)₂(bpp)₆] · (btc)₂ · 25H₂O}_n (Ι). Single crystal X-ray diffraction analysis reveals that the complex Ι consists of 1D infinite cationic chains of [Ag(bpp)]_nⁿ⁺ and [Ag(H₂O)(bpp)]_nⁿ⁺ which are further linked into the cation layer of [Ag(bpp)]_nⁿ⁺ by Ag···π interactions. The noncoordinated btc³⁻ serves as template driving surrounding water molecules to aggregate into the anionic water layer. The neighboring anionic water layer and cationic layer were further alternately joined into a 3D sandwich-like framework by hydrogen bonding. In addition, the luminescent properties of Ι were investigated.

A novel coordination polymer containing hetero-metal ions, [NiNa₂(PDC)₂(μ-H₂O)(H₂O)₂]_n, where PDC is 2,3-pyridine dicarboxylate ion, has been synthesized. In the structure, the PDC ligand chelates and bridges two Ni(II) and two Na(I) centers. Two kinds of metal centers are connected by μ⁴-PDC and μ²-H₂O to form 2D coordination layers. Hydrogen bonds between coordination water molecules and carboxylate oxygen atoms further link these 2D coordination layers to form 3D supramolecular network.

The centrosymmetric dinuclear title complex [Hg₂Cl₄(dip)₂] was synthesized using the Schiff base bidentate ligand (E)-4-ethyl-N-(pyridine-2-ylmethylene)benzeneamine (dip) and mercury(II) chloride salts. It has been characterized by elemental analysis, X-ray diffraction, and UV-Visible and infrared spectroscopic techniques. The X-ray analysis shows that the title compound crystallizes in the monoclinic sp. gr. P2₁/n, Z = 2 with a = 7.8233(17) Å, b = 15.178(3) Å, c = 12.559(3) Å, β = 97.021(3)°. The Hg(II) ion has a distorted trigonal–bipyramidal coordination environment formed by the bischelating N-heterocyclic ligands, two bridging Cl atoms and one terminal Cl atom.

A synthetic route involving 4,6-dimethoxy-2-hydroxy-3-methylbenzoic acid (10) and 2,4-dimethoxy-6-hydroxy-3-methylbenzoic acid (11) has been investigated in the process of synthesis of the natural lichen substance namely, crocynol. Crystal structures of 10 and 11 were determined to confirm the ambiguous structures of the two isomers. Crystals 10 are monoclinic, sp. gr. P2₁/m, Z = 2. Crystals 11 are monoclinic, sp. gr. P2₁/c, Z = 4. In the crystal packing of 10, the molecules are arranged into chains along the a-axis formed only by van der Waals interactions, whereas in 11, the molecules are linked by O–H···O and C–H···O hydrogen bonds into chains along the b-axis and further stacked by π···π interactions with the centroid ···centroid distance of 3.6863(8) Å.

The title compound, tetraphenylborate salt of atropine (RS)-(8-Methyl-8-azabicyclo[3.2.1]oct-3-yl) 3-hydroxy-2-phenylpropanoate tetraphenylborate salt, was prepared by the reaction of (RS)-(8-Methyl-8-azabicyclo[3.2.1]oct-3-yl) 3-hydroxy-2-phenylpropanoate sulfate (2:1) salt with sodium tetraphenylborate in deionized water at ambient temperature through anion exchange reaction. Colorless crystals of the title compound suitable for X-ray structural analysis were obtained by slow evaporation from acetonitrile. The title compound crystallizes in the triclinic sp. gr. P1 with a = 9.7989(5) Å, b = 9.8203(5) Å, c = 18.6099(9) Å, α = 81.356(2)°, β = 80.616(2)°, γ = 67.704(2)°, V = 1627.05(14) ų, Z = 2.

The molecular structure of (2E)-ethyl 2-((4-(cyanomethoxy)benzylidene)hydrazono)-3,4-dimethyl-2,3-dihydrothiazole-5-carboxylate was determined using X-ray diffraction. The crystals are triclinic: sp. gr. P1; Z = 2; the unit cell parameters a = 8.4747(7) Å, b = 8.9382(8) Å, c = 11.9913(10) Å. The title compound has two C–H···O type intramolecular hydrogen bonds, one C–H···O and one C–H···N type intermolecular hydrogen bonds. For theoretical calculations, the molecular structure was investigated by DFT/B3LYP method with 6-311G(d) and 6-311G(d, p) basis sets. The calculated and experumental results (bond lenghts, bond angles, and dihedral angles) were compared with each other. Total energy, dipole moment, and mulliken atomic charges were calculated using two different basis sets.

Six 3-substituted hydrazone derivatives [R = −OCH₃ (1), −NH₂ (2), −NO₂ (3), −F (4), −Cl (5), and −Br (6)] were synthesized by condensation reaction. Their structures were elucidated by ¹H NMR, FT-IR and UV-Vis spectroscopy. The synthesized compounds were further evaluated for their α-glucosidase inhibitory activity. Strong activity was found for 1 and 3. The crystal structure of 1 was determined by single crystal X-ray diffraction: a = 6.9743(1) Å, b = 18.3627(3) Å, c = 12.0207(2) Å, β = 96.087(1)o, sp. gr. P2₁/c, Z = 4. The molecule of 1 is twisted with the dihedral angle between the two phenyl rings being 51.91(4)°. In the crystal packing, the molecules are linked into chains by C–H···π interactions.

Two V-shaped ligands with N-heterocycles, bis(4-(1H-imidazol-1-yl) phenyl)methanone (1), and bis(4-(1H-benzo[d]imidazol-1-yl)phenyl)methanone (2) have been synthesized and characterized by elemental analyses, IR and 1H NMR spectroscopy. Crystal structures of 1 and 2 have been determined by X-ray diffraction. The crystal of 1 is monoclinic, sp. gr. P2₁/c, Z = 4. The crystal of 2 is orthorhombic, sp. gr. Fdd2, Z = 8. X-ray diffraction analyses show that the V-shaped angles of 1 and 2 are 122.72(15)° and 120.7(4)°, respectively. Intermolecular C–H···O, C–H···N, C–H···π, and π···π interactions link the components into three-dimensional networks in the crystal structures.

A new hydrazone derivative was synthesized and characterized by IR, UV-Vis spectroscopy, elemental analysis and single-crystal X-ray diffraction. The compound was established to reveal antibacterial activity. The compound (C₁₈H₁₆N₄O₂S) crystallizes in monoclinic crystal system with C2/c space group. The molecular structure is stabilized by a C–H···O intermolecular hydrogen bond. Quantum chemical calculations based on DFT/B3LYP/6-31G(d, p) were carried out and the results were compared with the experimental data. The calculated vibrational frequencies were used to determine the types of molecular motions associated with each of the observed experimental bands. UV-Vis absorption spectra of the compound calculated by TD-DFT have been ascribed to their corresponding molecular structure and electron transitions.

The reaction of cis-[ReO₂I(PPh₃)₂] with tert-butyl isocyanide in benzene led to the isolation of the complex [ReI₃(CN-t-Bu)₃(PPh₃)] (1). The complex is unusual since it contains bulky ligands with large cone angles, i.e. three iodides, three isocyanides with tert-butyl groups and a triphenylphosphine as ligands in a seven-coordinate geometry around the rhenium(III) metal ion.

The title compound 6-phenyl-4-(p-tolyl)pyridin-2(1H)-one was synthesized via one-pot, three component reaction of (E)-1-phenyl-3-(p-tolyl)-2-propen-1-one, ethyl 2-nitroacetate and ammonium acetate in refluxing ethanol, as a shiny green crystalline solid in 83% yield. Its structure was characterized by spectral studies and unambiguously corroborated by X-ray diffraction crystallography. The crystals of title compound are monoclinic, sp. gr. P2₁/n, a = 11.8346(7) Å, b = 13.4413(9) Å, c = 17.7626(10) Å, β = 99.479(5)°, and Z = 8. All the rings in molecule of the title compound are planar. Hydrogen interactions play significant role in stabilizing the crystal structure and the supramolecular aggregate of molecules is facilitated by strong N–H···O and C–H···O type of hydrogen interactions.

A new mixed-valence coordination polymer [Cu₃(SCN)₄(DMSO)₂]_n (SCN^– = thiocyanato and DMSO = dimethyl sulfoxide) was prepared and characterized by single crystal X-ray diffraction method. The in situ formation of thiocyanate during the synthesis induces reduction of a part of Cu(II) to Cu(I). The three-dimensional structure of the binuclear thiocyanato bridged compound provided an example of pseudohalide materials containing two different environments for both copper centers.

Single crystal of Li[UO₂(CH₃COO)₃]₃[Co(H₂O)₆] was prepared and found to crystallize in the monoclinic crystal system in the sp. gr. C2/c, with Z = 2, and unit cell parameters a = 22.1857(15) Å, b = 13.6477(8) Å, c = 15.6921(10) Å, β = 117.842(9)°, V = 4201.3(4) ų. The crystal was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and differential scanning calorimetry. The single crystal X-ray diffraction analysis revealed that the crystal has a lamellar structure in which a cobalt hydrate is sandwiched within the Li[UO₂(CH₃COO)₃]₃^2- chains. Furthermore, the room temperature photoluminescence spectrum of the complex was investigated in the solid state.

Yeast Hsp104 is an ATP-dependent molecular chaperone, which can solublize and rescue denatured proteins from aggregates into active form by cooperating with Hsp70 and Hsp40 chaperones. Moreover, overexpression of Hsp104 of Saccharomyces cerevisiae (ScHsp104) cures the yeast [PSI⁺] prion due to the completely dissolution of the prion seeds, demonstrating ScHsp104’s potential to clear amyloid-like protein aggregates, thus making ScHsp104 a promising medication approach for human amyloidogenic neurodegenerative diseases. Because the working mechanisms for ScHsp104’s activities have not been clearly elucidated yet, crystallographic determination of ScHsp104 stands for great significance. Here, the expression, purification and crystallization of the N-terminal domains of Hsp104 from yeast Candida albicans (CaHsp104N) and S. cerevisiae (ScHsp104N) are described. The CaHsp104N crystals diffracted to 1.54 Å and belonged to the sp. gr. P3₂21 or P3₁21, with unit cell parameters of a = 55.213 Å, c = 109.451 Å. The data of the ScHsp104N crystals were collected to the resolution of 2.53 Å in the sp. gr. C2, with unit cell parameters a = 148.587 Å, b = 66.255 Å, c = 74.577 Å, β = 107.369°. The phase of ScHsp104N is determined by the molecular replacement method using CaHsp104N as the search model.

The 4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) crystal which was candidate for generating and detecting terahertz (THz) wave was grown by slope nucleation method (SNM). The functional groups of DAST were identified by Fourier Transform Infrared (FTIR) studies. Macroscopic steps and streaks on the (001) face were found by scanning electron microscope (SEM). Different patterns of etch pits under different chemical etchants were studied by optical microscope. Widely tunable THz waves ranging from 0.38 to 18.10 THz were generated from 0.5 mm-thick DAST crystal. The maximum output energy was 345.4 nJ/pulse at 3.39 THz and the conversion efficiency was 8.44 × 10^–5.